Well boring drill



Aug. 29, i967 R. L. POMEROY l 3,338,321

WELL BOR ING DRILL Filed Feb. 23, 1955 3 Sheets-Sheet l INVENTOR ATTORNEYaSl Aug. 29, 1967 3 Sheets-Sheet 2 Filed Feb. 23, 1965 ENTOR Lipo/meier l o Bm/,M

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ATTORNEYS United States Patent Office 3,338,321 Patented Aug. 29, 1967 3,338,321 WELL BORING DRILL Robert L. Pomeroy, Rome, Italy, assigner of twentydve percent to Duif Stewart Filed Feb. 23, 1965, Ser. No. 434,505 28 Claims. (Cl. 17E- 92) ABSTRACT OF THE DISCLOSURE A well boring drill having a cutting means operatively secured to the lower end of a shaft and moved in an arcuate path about a horizontal axis passing through the shaft above the cutting means by a reciprocating drive means. Means is provided to use the circulating mud as the reciprocal drive, and the shaft is preferably exible.

Summary of lhe invention This invention relates to a well-boring drill and more particularly to a well-boring drill utilizing a reciprocally driven cutting means. The invention can be summarized as comprising a shaft having a rst axial passageway extending therethrough; cutting means operatively connected to the lower etnd of the shaft for reciprocal arcuate movement about a horizontal axis passing through the shaft above the cutter head; and means for reciprocally driving the cutting means independently of the shaft in an arcuate movement about a horizontal axis passing through the shaft above the cutter head. The invention also contemplates using flexible shaft sections for at least part of the shaft, stabilizer means to prevent rotation of the exible part of the shaft, and reciprocal drive means utilizing the circulating mud.

The purpose of this invention is to provide a more rapid and eicient meth-od of cutting a vertical hole through rock in the search for water, oil or other minerals. Whereas conventional drilling methods depend on either the vertical rotation of a drill-bit, or the percussion of a cutting head, the present invention would cut a vertical hole by the sawing action of a chain or tooth-faced links moving down one side of the Well, around a guide at the lbottom of the hole and up the other side of the well. This concept differs radically from the principle of the endless chain as in a chain-saw in that the ends are not joined but are connected to drive shafts on either side of the center shaft. These drive shafts alternate in drawing the cutting links across the face of the hole and upward for a limited distance after which the stroke is reversed and the chain of links is drawn up the opposite side of the hole. As the hole thus drilled would be elliptical rather than round, a method of adding a gradual rotary motion to the entire device has been added to the claims so that each stroke would tend to cut away slightly from the flatter side of the ellipse.

As this device is preferably designed to operate with a exible mud-hose rather than a rigid drill stern, it is essential that no rotary motion be imparted to the mudhose. Thus, this novel drilling device could be used as a pilot borer of an elliptical hole which, because of the shape of the hole, would prevent rotation of the device or the ilexi-ble shaft about its longitudinal axis (the hole would then be reamed out), or as a borer of a round hole as long as the lower portion of the shaft or drill stem is provided with a device to effect gradual rotation yabout its longitudinal axis.

It is a further object of this invention to provide a shaft which comprises an upper ilexible section, a rigid intermediate stabilizing section coupled to the upper flexible section and a lower cutting section coupled to the stabilizing section so as to rotate independently thereof.

Heretofore, the most common type of drill was a rotary drill with a bit attached to the lower end of a hollow shaft and turned by rotary movement imparted to the shaft from the rig at the surface. The shaft not only drives the bit but also carries the mud which is pumped down into the well to cool the bit, to bring up the tailings and to maintain pressure within the well. For its tremendous strength, the shaft is the weakest and most troublesome link of the rotary system. Its length, which may reach two or more miles into the ground, requires tremendous strength just to withstand its own dead weight let alone the added stresses and strains of torsion as it revolves, especially during the drilling of an off-set hole. Breakage is common and, of course, time-consuming to repair or bypass. Just to remove the shaft from the hole to repair a drill bit is an operation which takes more and more of the drilling time as the depth of the well increases.

It can easily be seen by utilizing an upper ilexible section, the weight of the shaft is considerably reduced. The size of the cutting section does not substantially change froml one drilling operation to another. Likewise, the stabilizing section, which gives Weight and direction to the cutting section, is substantially the same size for each drilling operation. Accordingly, as the depth of the well increases, the only section which is increasing in length, and hence in weight, is the upper flexible section which weighs far less than a comparable upper section of an ordinary rotary well-drilling shaft. The upper section is preferably secured to the stabilizing section by a threaded coupling. Accordingly, it is realized that the upper section must be strong enough to raise the stabilizing section and the cutting section. The cutting section is connected to the stabilizing section by a swivel joint so that it can rotate independently of the stabilizing section. Therefore, the upper section does not have to have the strength which is necessary to impart a rotational movement to the lower two sections.

In the preferred embodiment of the invention the cutting means comprises a chain member having an outwardly facing toothed surface that accomplishes the actual drilling of the well as it is scoured back and forth -by the reciprocating drive means. While the chain member comprises a plurality of interconnected link members, it is also an object of this invention to provide a flexible belt having cutting teeth embedded therein and protruding therefrom. Moreover, the cutting means could comprise a hemispherical member having a plurality of teeth on its curved surface, the upper flat surface of the hernispherical member being pivotally and centrally attached to the shaft with the drive means secured thereto at substantially diametrically opposed edges lof the upper ilat surface for imparting a reciprocal rocking motion to the hemispherical member.

The scouring, reciprocating motion of the cutting means provides advantages over present techniques used in drilling wells. The actual cutting time of each section of the cutting means is reduced thereby providing each cutting section with a longer period of time to cool down before it is in a cutting position again. Moreover, the upward motion of the cutting means would clear -the hole by moving the tailings upwardly with the stream of mud rather than grinding them around and around as a rotary bit does. Furthermore, the reciprocating motion provides a different and improved cutting action than that of end-` less chains, such as shown in the patent to Holt, 2,134,- 164, of Oct. 25, 1938. Likewise, the possibility of the device binding is reduced not only by the reciprocating motion of the cutting means, but also by the fact that the bits become dull and have to be changed. Although the proposed cutting means in the instant application would last longer because the actual cutting time of each section of the cutting means would be intermittent rather than continuous, as in the case of the rotary drill, it would nevertheless have to be changed at some point. In a rotary drilling operation, or any other type of operation utilizing rigid shaft sections, the bit-changing operation may take hours inasmuch as the entire length of the shaft must be hoisted, clamped, unscrewed and racked section by Section. In the instant case, when the bits are changed, the flexible upper section can simply'be wound up on a drum or coiled on the ground near the ring until the last two rigid sections are reached. These rigid sections are then removed and racked in the usual manner. It will be appreciated that this procedure involves considerably less time than the former bit-changing operations.

It is also an object of this invention to provide a means for reciprocally driving the cutting means. Probably the mist direct method of power transmission would be to use steel cables attached at one end to the cutting means and at the other end to a winch or rocking arm on a rig above the ground. It will be appreciated, however, that this would be quite awkward and ineicient due to the resistance offered by the long column of mud through which the cables would have to move. Therefore, it is an object of this invention to provide a reciprocating driving means which `preferably utilizes the circulating mud as the power for driving the cutting means. Accordingly, the mud is alternately directed through two cylinders associated with the cutting section of the shaft. The movement of each piston in the cylinders, having one end of the cutting means attached thereto, is 180 out of phase with the other piston so that the reciprocating motion of the pistons is transmitted to the cutting means. In view of the fact that at some depths the mud may not be sufciently fluid because of the tremendous pressure to drive the cutting means efficiently, it is also an object of this invention to provide other drive means which would not be affected by this tremendous pressure.

A well bored by the reciprocating action of the cutting means would be oval rather than round. Such a configuration would result in difliculty both in removing the drill from the well and in encasing the well. Therefore, it is a further object of this invention to provide means for revolving the cutting section on its vertical axis so as to round the hole. Accordingly, a swivel joint is provided between the stabilizing section and the cutting section so that only the cutting section will be rotated. There are numerous means for accomplishing this rotation of the cutting section, but the most preferred means is to provide a plurality of fins attached to the cutting section and extending into the path of the flowing mud. The mud impinging upon the ns will cause the shaft to rotate in a predetermined direction.

As mentioned above, the cutting section is connected to the stabilizing section by a swivel joint so that the cutting section can rotate independently of the stabilizing section. However, to insure that the rotatable movement of the cutting section is not imparted to the upper flexible section through the intermediate stabilizing section, it is an object of this invention to provide means for stabilizing the intermediate or stabilizing section. Such means is designed to prevent rotation while allowing axial movement of the stabilizing section so as to prevent the upper section, directly secured to the stabilizing section, from becoming hopelessly twisted. Accordingly, a plurality of stabilizing Wheels rotating in a plane substantially parallel to the axis of the shaft and having an axis of rotation substantially perpendicular to the axis of the shaft are associated with the stabilizing section so as to be movable between an outer position engaging the inner wall of the well and an inner position substantially adjacent to the shaft.

It will also be appreciated that the well boring drill can be modilied to provide a coring device through the utilization of a pair of cutting means operated by a pair of drive means with a core receiving hollow cylinder located therebetween for obtaining a core sample.

There are many advantages offered by this improved well boring drill. The well may be drilled faster due to the reduced time in changing bits with a fewer number of men required to operate the rig. Furthermore, the risk of breakage is reduced by this type of drill. The cutting means is far superior due to the increased area of the cutting surfaces with better cooling and, consequently, longer life. Moreover, the cutting stroke offered by this reciprocating drive means is superior to conventional cutting strokes. The equipment can be transported and handled much easier due to the reduced weight and size thereof. Finally, this well boring drill can be easily adapted to conventional rigs with minimum redesigning of the rig.

These and other objects of this invention are more clearly depicted in the following detailed description having specic reference to the attached drawings in which the embodiments of the invention are shown, not to limit the scope of the invention in any respect but so that the principles thereof might be more clearly demonstrated.

In the drawings:

FIGURE 1 is a schematic drawing of the well boring drill illustrating invention in use;

FIGURE 2 is a sectional plan view taken through the cutting section in the area designated by the lines 2-2 of FIGURE 1;

FIGURE 3 is a diagrammatic view illustrating the passageways of the drive means and cylinders with part of one cylinder broken away to disclose the interior thereof;

FIGURE 4 is a schematic drawing showing the operation of the drive means shown in FIGURES 2 and 3;

FIGURE 5 is a perspective view of one -cutting link;

FIGURE 6 is a fragmentary side elevational sectional view taken vertically through the lower end of the cutting section;

FIGURE 7 is a perspective view of a modified cutting tooth;

FIGURE 8 is a perspective view of the modified cutting means;

FIGURE 9 is a perspective view of still another modified cutting means shown associated with the shaft and drive means;

FIGURE 10 is a side elevational view of the upper part of the cutting section with parts broken away to disclose the means for rotating the shaft;

FIGURE 11 is a fragmentary perspective view of the stabilizing section with parts broken `away to show the stabilizing means;

FIGURE 12 is a plan sectional view taken through the cutting section in the area designated by the lines 2 2 of FIGURE 1 and showing the cutting section adapted for coring.

Referring to FIGURE 1, a shaft 20 is shown positioned vwithin a well 22 which has been previously bored, the

well being larger than the shaft so that the shaft is disposed inwardly of the inner walls 24 of the well. The shaft 20 has a rst axial passageway 26, shown in FIG- URES 2 and 6, extending therethrough for circulating mud.

The shaft 20 comprises an upper exible section 28, an intermediate stabilizing section 30 and a lower cutting section 32. The upper flexible section is a hose preferably made of heavy reinforced plastic or rubber having sufficient strength to raise the lower two sections of the shaft. The upper end of the flexible section 28 is secured to the drilling rig, not shown, while the lower end 34 is secured by a coupling 36 to the upper end 38 of the intermediate stabilizing section. The stabilizing section and the lower cutting section are made of rigid material, such as steel, as compared to the flexible upper section. The steel sha-ft of the stabilizing section gives weight and direction to the cutting section. The stabilizing section is joined to the cutting section by a swivel joint 40 which enables the two sections to rotate independently of each other. The cutting section is the work end of the drill shaftv having a' drive means 42 and a cutting means 44 operatively associated therewith. The steel shaft of the cutting section in combination with the steel shaft of the stabilizing section provide weight for achieving an eective cutting action.

In order to impart an effective cutting stroke to the cutting means 44, it has been found that it is desirable to drive the cutting means reciprocally. Accordingly, as shown in FIGURES 2, 3 and 4, the drive means in the preferred embodiment of the invention comprises a pair of cylinders 48, each having an inner wall 50 defining a cavity therein for slideably receiving a piston head 52. A piston stem 54 is attached at one end 56 to the piston head 52 and at the other end 57 to opposite sides of the ends 58 of the cutting means 44. By reciprocally moving the piston heads 52 within the cylinders 48 approximately 180 out of phase with each other, a reciprocal motion is imparted to the cutting means.

Preferably, the power utilized for reciprocally moving the piston heads is the circulating mud. Accordingly, the mud is alternately directed into each cylinder so as to drive the piston, i.e., the piston head and piston stem, upwardly, the upward motion of one piston resulting in a downward motion of the other piston through the interconnecting cutting means. As shown in FIGURES 2 and 3, the axial passageway 26 preferably -becomes bifurcated adjacent these cylinders so as to minimize the space utilized for the drive means. Each cylinder has an upper port 60 and a lower port 62 communicating with thebifurcated axial passageway 26. FIGURE 4 is a schematic diagram showing the operation of driving means. The passageway 26 in FIGURE 4 is divided into two sections 63 and 65 representing the two bi-furcated passageways shown in FIGURE 3. A barrier 64 extends across each bifurcated section of the shaft between the points of communication with the up-per 60 and lower 62 ports. Mud alternately enters the upper port and then exits through the lower port so as to continue on through the rst axial passageway 26 until it dispersed at the lower end of y the shaft. While the mud is entering through the upper port of one cylinder, mud which previously entered the other cylinder through the upper port is being driven out of that cylinder through the lower port as the piston head moves downwardly in the cylinder. Thus, the ports of each cylinder are cyclically opened and closed with the ports of the other cylinder being 180 out of phase with the ports of the first cylinder.

A valve means 66 is provided for alternately opening 'and closing the ports. As illustrated, the valve means is a slide valve preferably operated by the pistons themselves, although it is appreciated that the valves could be operated by other means. As seen in FIGURE 4, the slide valve 66 is positioned between the bifurcated passageway and the cylinders. The slide valve has a plurality of openings 68 which communicate the upper and lower ports of the cylinders to openings 70 in the bifurcated passageways. In order to open and close the ports, the slide valve 66 is provided with an upper nob 72 and a lower nob 74 extending through slots 76 in the cylinder wall into position for engagement by the piston head 52. The upper nob 72 extends into the upper part ofthe cylinder 48 in a position for engagement by the top of the piston head 52 while the lower nob, attached to the slide valve 66 above the openings 68, extends into the lower parts of the cylinder. It will be appreciated that the nobs could be located in various other positions and actuated by protrusions from the piston stem. VIn fact the slide valve could be actuated by electrical means tripped by the piston. Likewise, any type of valve means which could open or close a port is to be considered within the intended -scope of this application.

In operation, as further illustrated in FIGURE 4, the mud ows through both bifurcated sections of the axial passageway. Inasmuch as one of the openings 68 of the slide valve is aligned with the upper port 60 of the left cylinder and the upper opening 70 of the axial passageway, mud ows into the left cylinder driving the piston head upwardly with the resulting downward movement of the right piston head. The right piston head moves downwardly until it strikes the lower nob 74 whereupon it drives the slide valve downwardly closing the upper port of the left cylinder and the lower port of the right cylinder. At the same time, the upper port of the right cylinder and the lower port of the left cylinder are opened so that mud now llows into the right cylinder under the piston and drives it upwardly. The upward motion of the right piston results in the downward motion of the left piston. The downward motion of the left piston forces the mud which had previously entered the left cylinder out through its lower port 62 into the passageway 26 of the bifurcated section wherein it ows downwardly to a point where the bifurcated sections rejoin and from there to the free end of the shaft. The upward movement of the right piston and piston stem brings the upper surface 0f the piston head into engagement with the upper nob 72 thereby driving the slide valve into its upper position shown in FIGURE 4 wherein the entire operation is alternated so that the mud now drives the left piston upwardly. Accordingly, a continuous reciprocating mo tion is imparted to the cutting means. It may also be desirable to provide a snap spring, not shown, for carrying the slide valve over dead center and for holding it in its upper position so that it wont fall and close olf some of the ports. k

While the foregoing is the preferred driving arrangement, it is within the scope of this invention to include any other type of drive means which could eifect the reciprocating motion of the cutting means. Accordingly, it may be desirable to utilize a turbine in which the rotary motion of the shaft is translated into a reciprocating motion driving the cutting means. Furthermore, other fluids or gases could be used to drive the piston if for some reason the pressure prevents the mud from being suiciently fluid. Likewise, an electric drive, such as a series of electromagnets, could be utilized to drive the pistons.

As shown in FIGURE 1, the cutting means 44 comprises a chain member 78 having an outwardly facing toothed surface 80 and two free ends 58. The free ends of the chain member are operatively secured to the reciprocating drive means, and as illustrated more particularly, they are attached to the ends of the piston stems 54. As shown in FIGURE 5, the chain member comprises a plurality of interconnecting link members 82 extending in a substantially end-to-end relationship with the outer surface 84 of each link member having a plurality of cutting teeth 86 secured thereto, preferably of pyramid-shape. As further illustrated in FIGURE 6, the chain memmber 78 is received in a guide 88 at the lower or free end 90 of the cutting section 32. The groove is a stationary groove, although within the scope of the invention it could be rotatable or even a smooth or sprocketed wheel. While the stationary groove is stronger, it does have the disadvantage of offering more friction to the chain member. Each link member 82 has at least one opening 92 extending therethrough for enabling the mud to ow through the link member. Not only does the owing mud act as a lubricant and a coolant, but it also removes dirt which might become stuck between the cutting teeth 86. The rocking motion of the cutting means moves the tailings upwardly with the stream of mud thereby clearing the drilled hole so as to improve the effectiveness of the cutting.

Although the cutting teeth 86 are shown as being pyramidal, it is also within the scope of the invention to use chisel-shaped cutting teeth 94, shown in FIGURE 7, in which the cutting teeth would be secured to the link member in a position in which the top cutting edge of ridge 96 of the tooth would be angularly inclined to the axis of movement of the link member 82 and to a perpendicular to the axis of movement of the link member. It is also within the scope of the invention to use a exible belt 98 having cutting teeth 100 of any suitable shape, embedded therein and protruding therefrom, as illustrated in FIGURE 8. Moreover, as disclosed in FIGURE 9, a cutting means could be provided comprising a hemispherical member 102 having a plurality of teeth 104 of any desirable shape on its curved surface 106. The upper fiat surface 108 of the hemispherical member 102 is shown pivotally attached to the shaft 20. In this embodiment, the piston stems 54 would be secured at substantially diametrically opposed edges 110 of the hemispherical member so that a reciprocating rocking motion could be imparted thereto.

When a chain member 78, such as illustrated in FIG- URE l, is used to drill a deep well, an oval well rather than a round well would be bored. Resulting difficulty would occur both in removing the drill and in casing the well. Therefore, means to revolve the cutting section on its vertical axis, even if very slowly, is provided so that a round well will be bored. It is only necessary that the cutting section be revolved, and accordingly the stabilizing section is connected to the cutting section by a swivel joint 40. The means for rotating the stabilizing section preferably comprises a plurality of fins 112 secured to the shaft and protruding therefrom into the path of the iiowing mud, as shown in FIGURE l0. The fins are positioned in a plane upwardly extending and angularly inclined from the longitudinal axis of the shaft and the perpendicular to the longitudinal axis of the shaft so that the mud striking the fins will cause the shaft to rotate about its axis. Inasmuch as the mud fiows down the first axial passageway 26 of the shaft, through the lower end 90 of the shaft, and thereafter up the outer surface 114 of the shaft 20 carrying with it the tailings, the fins may protrude from the shaft either internally into the passageway 26 or externally into the path of mud flowing upwardly ybetween the outer surface 114 of the shaft and the inner walls 24 of the well.

An additional means of revolving the cutting section would be to use the chisel-shaped cutting teeth 94 so that the section would revolve because of the inclination of the chisel-shapel cutting tooth from the axis of movement as measured by its top edge 96. It will be appreciated that within the scope of the invention other means may be utilized to rotate the cutting section. Such means could, in fact, be operatively connected to the reciprocating pistons so as to convert the reciprocating motion of the pistons into a rotary motion as by a plunger and ratchet means.

While it is desirable to rotate the cutting section, it is not necessary to rotate the intermediate stabilizing section. In fact, the stabilizing section is preferably prevented frorn rotation so as to keep the upper section from becoming hopelessly twisted. Accordingly, means is provided for preventing rotation of the stabilizing section while allowing axial movement thereof so that the stabilizing section can move downwardly as the well is bored deeper. To accomplish this stabilizing function a pair of rotatable toothed wheels 116 are provided, each having its plane of rotation substantially parallel tothe axis of the stabilizing shaft so that when the toothed wheels are moved into an outer position in engagement with the inner wall of the well, the toothed wheel can easily ymove up and down the wall while at the same time preventing rotation around the inner wall of the well. Any suitable means rnay be employed to move the toothed wheels between an outer position in engagement with the inner wall of the well and an inner position disposed from the inner wall. The outer position must be assumed when mud is fiowing through the shaft to operate the cutting means,

while the inner position must be assumed when the drilling is ceased and the shaft is being removed from the well. Accordingly, it can be seen that any type of mechanism can be used to effect this movement of the wheels, although preferably the movement thereof is effected by the flow of mu-d so as to keep the operation of the drill as simple as possible.

In the preferred form of the invention, therefore, an elbow-joint 118 operating in a plane substantially parallel to the axis of the stabilizing section is provided. The elbow-joint has a first leg 120 and a second leg 122 pivotally connected at their adjacent ends 124. The toothed wheel 116 rotates about the pivotal connection 126 between the adjacent ends of the two legs, and each adjacent end 124 has a groove 128 cutl therein for receiving the wheel 116. A hollow cylinder having means defining a cavity therein is positioned within the stabilizing section. A piston head 132 having a piston stem 134 attached thereto is positioned within `the cylinder cavity with the piston stem lying approximately parallel to the axis of the stabilizing section. The other end 136 of the first leg 120 is pivotally attached to the stabilizing section while the other end 138 of the second leg 122 is secured to the free end 140 of the piston stern 134. The cylinder has a first end 142 and a second end 144 with the piston stem 134 extending through the first end 142. The second end 144 of the cylinder is operatively connected to the first axial passageway extending through the stabilizing section by a second passageway 146 so that mud can liow into the cylinder from the axial passageway. Initially, the first and second leg, along with the piston stem, lie in a recess 148 substantially parallel to the stabilizing section axis. When mud begins to flow through the first axial passageway 26, it enters the hollow cylinder 130 through the second passageway 146 at the second end 144 of the cylinder and drives the piston head 132 towards the first end 142 of the cylinder. Inasmuch as the other end 136 of the first leg is pivotally attached to the stabilizing section, the movement of the piston head and the piston stem forces the adjacent ends 124 of the first leg and second leg, along with the toothed wheel 116, outwardly until the toothed wheel engages the inner wall of the well. The continuous flow of mud keeps the toothed wheel in its stabilizing position until the iiow of mud is cut off.

While only the means for driving one toothed wheel has been described, it will be seen that at least two toothed wheels are necessary, placed on opposite sides of the shaft so that the shaft will be held coaxial with the well.

If a greater number of toothed wheels are used, they should be equally spaced around the shaft to assure that the shaft will be centered within the well. A wheel operating means such as described above is associated with each wheel although only one such operating means is described herein.

When the flow of mud is cut off `and the stabilizing section is removed from the well, the inner walls 24 of the well will knock the toothed wheel back into its original position substantially adjacent the stabilizing section. It will be appreciated that resilient means 150 could be provided which, for instance, would be secured within the cylinder between the first end thereof and rthe piston head so as to move the piston head towards the second end of the cylinder. Obviously, other common means may be provided for stabilizing the stabilizing section.

During the ycourse of drilling a well, it may be desirable to take coring samples. Accordingly, the present invention may be adapted to a coring device by simply incorporating a pair of `drive mechanisms, as shown in a plan view in FIGURE l2. Such an arrangement would involve having a rst drive mechanism with a first pair of cylinders and piston means 152 operating off of a first passageway 154 and a second pair of cylinder and piston means 156 operating off of a second passageway 158. The first 154 and second 158 passageways are the bifurcated portion of the main passageway through the shaft 20. ItA will be seen that each of the pistons can easily operate off one passageway and the purpose of bifurcating the passageway in the preferred embodiment of the invention is strictly a space-saving arrangement. The central shaft 160 shown in FIGURE 12 is not an extension of the main passageway 26 of the shaft but rather is a core receiving cylinder. Likewise, any other type of drive mechanism which might be used to impart a reciprocal motion to the cutting means could be used for coring by incorporating a pair of such drive mechanisms.

While a preferred form of the invention has been illustrated in the drawings and discussed above, it should be adequately clear that considerable modification may 'be made thereto without departing from the principles of the invention. Therefore, the foregoing should be considered in an illustrative'sense rather than a limiting sense, and accordingly, the extent of this invention should be limited only by the spirit and scope of the claims appended hereto.

I claim:

1. A well boring drill comprising:

a shaft having a first axial passageway extending therethrough;

cutting means operatively connected to the lower end of the shaft for reciprocal -arcuate movement about a horizontal axis passing through the shaft above the cutting means; and

means for reciprocally driving the cutting means independently of the shaft in an arcuate movement about a horizontal axis passing through the shaft above the cutting means.

2. The Well boring drill defined in claim 1 wherein the shaft comprises an upper flexible section, a rigid intermediate stabilizing section coupled to the upper flexible section, and a lower cutting section coupled to the stabilizing section so as to rotate independently thereof.

3. The well boring drill defined in claim 1 wherein the cutting means comprises a hemispherical -member having a plurality of teeth on its curved surface, the upper fiat surface of the hemispherical member being pivotally and centrally attached to the shaft and being operatively secured at substantially diametrically opposed edges thereof to the drive means for imparting a reciprocating rocking motion to the hemispherical member.

4. The Well boring drill defined in claim 1 additionally comprising stabilizing means secured to the stabilizing section for substantially preventing rotatable movement thereof while allowing axial movement thereof.

5. The well boring drill defined in claim 4 wherein the stabilizing means comprises at least a pair of rotatable toothed wheels each having its plane of rotation su'bstantially parallel to the axis of the stabilizing shaft and means to move the toothed wheels between an inner position disposed from the inner wall of the well and an outer position in engagement with the inner wall of the well.

6. The well boring drill defined in claim 5 -wherein the means to move each stabilizing wheel comprises an elbow-joint operating in a plane substantially parallel to the axis of the stabilizing section and having a rst leg and a second leg pivotally connected at their adjacent ends, each adjacent end having an axial groove cut therein for partially receiving the wheel, the wheel rotating above the pivotal connection between the adjacent ends, the first leg Ibeing pivotally attached at the other end to the stabilizing section, and a hollow cylinder having a piston head slideably positioned therein with a piston stem, positioned substantially parallel to the axis of the shaft, attached at one end to the piston head and lat the other end to the second leg and extending through the first end of the cylinder, the second end of the cylinder having means defining a second passage-way extending between the first axial passageway and the hollow cylinder whereby part of the mud flowing through the first axial passageway in the shaft will enter the hollow cylinder through the second passageway at the second end thereof and move the piston head and piston stem in the direction of 4the first end of the cylinder causing the first and second legs to be moved from a first position in which the legs lie adjacent the stabilizing section to -a second position in which the disposed ends of the first and second legs are moved toward each other in a plane substantially parallel to the longitudinal axis of the stabilizing section and the adjacent ends of the first and second legs are moved outwardly from the stabilizing section until the toothed wheel engages the inner wall of the well.

7. The Well boring drill defined in claim 6 additionally comprising resilient means positioned within the cylinder and Aurging the piston head in the direction of the second end of the cylinder so as to return the legs to their first position substantially adjacent to the stabilizing section when -mud is not flowing through the first laxial passageway.

8. The well boring drill defined in claim 1 wherein the cutting means comprises a chain member having an outwardly facing toothed surface and two `free ends, the free ends being operatively secured to the reciprocating drive means and wherein the lower `free end of the cutting section has a guide means for receiving the reciprocating chain member.

9. The well boring drill defined in claim 8 wherein the chain member comprise a flexible belt having embedded cutting tetth protruding therefrom.

10. The well boring drill defined in claim 8 wherein the chain member has a plurality of holes extending therethrough, each hole communicating with the axial passageway of the shaft when that portion of the chain member having the hole is positioned adjacent the lower end of the shaft passageway for allowing mud to cool the teeth and assist in removing the cuttings from the teeth.

11. The well boring drill defined in claim 8 wherein the guide means comprises means defining a groove in the lower end of the shaft, the chain member being received and reciprocally moving within the groove.

12. The well boring drill defined in claim 8 wherein the chain member comprises a plurality of interconnected link members extending in a substantially end-to-end relationship, each link member having an outwardly facing toothed surface.

13. The well boring drill defined in claim 12 wherein each tooth secured to the outwardly facing surface of the chain means has a pyramidal shape attached at its base to the chain member.

14. The Well boring drill defined in claim 12 wherein each tooth secured to the outwardly facing surface of the chain member has a chisel shape attached at its base to the chain member.

15. The well boring drill defined in claim 1 additionally comprising means for rotating the shaft and plurality of cutting means during the reciprocal motion of the cutting means.

16. The well boring drill defined in claim 15 wherein mud passes down the first axial passageway, out the bottom of the shaft, and thereafter up the outer surface of the shaft between the shaft and the inner wall of the drilled well and wherein the rotating means comprises a plurality of fins secured to and protruding externally from the outer surface of the shaft in a plane upwardly extending, angularly inclined from the longitudinal axis of the shaft, and angularly inclined from a perpendicular to the longitudinal axis of the shaft.

17. The well boring drill defined in claim 15 wherein mud passes through the axial passageway of the shaft and wherein the rotating means comprises a plurality of fins secured to the walls defining the first axial passageway of the shaft and protruding internally therefrom in a plane downwardly extending, angularly inclined from the longitudinal axis of the shaft, and angularly inclined from a perpendicular to the longitudinal axis of the shaft.

18. The well boring drill defined in claim 15 wherein the cutting means comprises a plurality of chisel-shaped teeth having a pair of flat side walls angularly inclined with respect to each other and converging to a cutting ridge and wherein the rotating means comprises the chiselshaped teeth having the cutting ridge angularly inclined from the direction of reciprocating movement and from the perpendicular to such direction.

19. The well boring drill defined in claim 1 wherein the reciprocating driving means comprises a pair of hollow cylinders, each having a piston head slideably positioned therein with a piston stem attached at one end to to the piston head and at the other end to opposite sides of the cutting means, and means to reciprocally drive the piston heads approximately 180 out of phase with each other so as to impart a reciprocal motion to the cutting means.

20. The well boring drill defined in claim 19 wherein each hollow cylinder has an upper port and a lower port communicating with the first axial passageway of the shaft and wherein the first passageway of the shaft has a barrier extending transversely thereacross at a point between the upper and lower ports of the cylinder, and additionally comprising means defining a valve member operatively associated with the two ports of both cylinders, and means operatively associated with the piston in one of the cylinders for alternately moving the valve between a first position wherein the upper port of one cylinder communicates with the first axial passageway of the shaft above the barrier while simultaneously the lower port of the other cylinder communicates with the first passageway of the shaft below the barrier and a second position wherein the lower port of the one cylinder communicates with the first passageway below the barrier while simultaneously the upper port of the other cylinder communicates with the first passageway above the barrier.

21. A well boring drill comprising:

a shaft having a first axial passageway extending therethrough, the shaft having at least two sections, rotatably independent of each other; and

means for preventing rotation of one section while allowing axial movement thereof comprising at least a pair of rotatable toothed wheels, each having its plane of rotation substantially parallel to the axis of the shaft and means to move each toothed wheel outwardly into engagement with the inner wall of the well, each moving means comprising an elbow-joint operating in a plane substantially parallel to the axis of the shaft and having a first leg and second leg pivotally connected at their adjacent ends, each adjacent end having an axial groove cut therein for partially receiving the wheel, the wheel rotating about the pivotal connection between the adjacent ends, the first leg being pivotally attached at the other end to the shaft, a hollow cylinder having a piston head slideably positioned therein with a piston stem, positioned substantially parallel to the axis of the shaft, attached at one end to the piston head and at the other end to the second leg and extending through the first end of the cylinder, the second end of the cylinder having means defining a second passageway extending between the first axial passageway and the hollow cylinder whereby part of the mud flowing through the first axial passageway in the shaft will enter the hollow cylinder through the second passageway at the second end thereof and will move the piston head and piston stern in the direction of the first end of the cylinder causing the first and second legs to be moved from a first position in which the legs lie adjacent the shaft to a second position in which the ldisposed ends of lthe first and second legs are moved toward each other in a plane substantially parallel to the longitudinal axis of the shaft and the adjacent ends of the first and second legs are moved outwardly from the shaft until the toothed l2 wheel engages the inner wall of the well;

cutting means operatively connected to the shaft; and

means for driving the cutting means.

22. The well boring )drill defined in claim 21 additionally comprising resilient means positioned within the cylinder urging the piston head in the direction of the second end of the cylinder so as to return the legs to their first position substantially adjacent to the stabilizing section when mud is not flowing through the first axial passageway.

23. The well boring drill defined in claim 21 wherein A the driving means reciprocally drives the cutting means independently of the shaft.

24. A well boring drill comprising:

a shaft having an axial passageway extending therethrough;

a hemispherical member having a plurality of teeth on its curved surface, the upper flat surface of the hemispherical member being pivotally and centrally attached to the shaft', and

means for imparting motion to the hemispherical member comprising a reciprocal drive means operatively secured to the hemispherical member at substantially diametrically opposed edges thereof for imparting a reciprocating rocking motion to the hemispherical member.

25. A well drilling bore comprising:

a shaft having an axial passageway extending therethrough, the shaft having at least two sections rotatably independent of each other, mud passing down through the axial passageway, out the bottom of the shaft, and thereafter up the outer surface of the shaft between the shaft and the inner wall of the drilled well;

fins attached to the shaft and protruding therefrom into the path of the flowing mud in a plane upwardly extending, angularly inclined from the longitudinal axis of the shaft, and angularly inclined from a perpendicular to the longitudinal axis of the shaft, the inclination of the fins being such that the mud striking the fins causes the shaft to rotate about its axis;

cutting means operatively connected to the shaft for reciprocal arcuate movement about a horizontal axis passing through the shaft above the cutting means; and

means for reciprocally driving the cutting means in an arcuate movement about a horizontal axis passing through the shaft above the cutting means.

26. The well boring drill defined in claim 25 wherein the driving means reciprocally drives the cutting means independently of the shaft.

27. The well boring drill comprising:

a shaft having a first axial passageway extending therethrough, the shaft comprising an upper flexible section, a rigid intermediate stabilizing section coupled to the upper flexible section, and a lower cutting section coupled to the stabilizing section so as to rotate independently thereof;

a stabilizing means secured to the stabilizing section for substantially preventing rotatable movement thereof while allowing axial movement thereof, the stabilizing means comprising at least a pair of rotatable toothed wheels, each having its plane of rotation substantially parallel to the axis of the stabilizing section and means to move each toothed wheel between an outer position in engagement with the inner wall of the well and an inner position disposed from the inner wall, each moving means comprising an elbow-joint operating in a plane substantially parallel to the axis of the stabilizing section and having a first leg and a second leg pivotally connected at their adjacent ends, each adjacent end having an axial groove cut therein for partially receiving the wheel, the wheel rotating about the pivotal connection between the adjacent ends, the first leg being pivotally attached 13 at the other end to the stabilizing section, a hollow cylinder having a piston head slideably positioned therein with a piston stem, positioned substantially parallel to the axis of the stabilizing section, attached at one end to the piston head and at the other end to the second leg and extending through the irSt end of the cylinder, the second end of the cylinder having means defining a second passageway extending between the rst axial passageway and the hollow cylinder, whereby part of the mud flowing through the first axial passageway in the shaft will enter the hollow cylinder through the second passageway at the second end thereof and will move the piston head and piston stem in the direction of the first end of the cylinder causing the :disposed ends of the rst and second legs to be moved from, a rst position in which the legs lie adjacent the stabilizing section to a second position in which the disposed ends of the first and second legs are moved toward each other in a plane substantially parallel to the longitudinal axis of the stabilizing section and the adjacent ends of the first and second legs are moved outwardly from the stabilizing section until the toothed wheel engages the inner wall of the well, and resilient means positioned within the cylinder and urging the piston head in the direction of the second end of the cylinder, so as to return the legs to their original position substantially adjacent to the stabilizing section when mud is not flowing through the first axial passageway in the shaft;

cutting means operatively connected to the cutting section; and

means associated with the cutting section for reciproand means to reciprocally drive the piston heads approximately 180 out of phase with each other so as to impart a reciprocal motion to the cutting means. 28. The well boring drill deiined in claim 27 wherein each hollow cylinder has an upper port and a lower port communicating with the rst axial passageway of the shaft and wherein the first passageway of the shaft has a barrier extending transversely thereacross between the points of communication with the upper and lower ports of the cylinder, and additionally comprising means dening a valve member operatively associated with the two ports of both cylinders, and means operatively associated with the piston in one of the cylinders for alternately moving the valve betweenl a rst position wherein the upper port of one cylinder communicates with the iirst axial passageway of the shaft above the barrier while simultaneously the lower port of the other cylinder communicates with the lirst passageway of the shaft below the barrier and a second position wherein the lower port of the one cylinder communicates with the first passageway below the barrier while simultaneously the upper port of the other cylinder communicates with the iirst passageway above the barrier.

References Cited UNITED STATES PATENTS 836,494 11/1906 Frieh et al 175-105 X 1,607,082 ll/1926 Howcott -107 X 1,613,555 1/1927 Boyd i 175-319 1,762,504 6'/ 1930 Bull 175-343 X 2,002,386 5/1935 Bannister 175-106 X 2,009,742 6/ 1935 Mitchell 175-329 2,105,091 1/1938 MacKay 175-327 X 2,119,661 6/1938 l Whalen 175--89 X 3,117,634 l/l964 Persson 1'75-106 X CHARLES E. OCONNELL, Primary Examiner. R. E. FAVREAU, Assistant Examiner. 

1. A WELL BORING DRILL COMPRISING: A SHAFT HAVING A FIRST AXIAL PASSAGEWAY EXTENDING THERETHROUGH; CUTTING MEANS OPERATIVELY CONNECTED TO THE LOWER END OF THE SHAFT FOR RECIPROCAL ARCUATE MOVEMENT ABOUT A HORIZONTAL AXIS PASSING THROUGH THE SHAFT ABOVE THE CUTTING MEANS; AND MEANS FOR RECIPROCALLY DRIVING THE CUTTING MEANS INDEPENDENTLY OF THE SHAFT IN AN ARCUATE MOVEMENT ABOUT 